Hair follicles on the scalp do not continuously produce hair. They cycle through a growth stage that can last two or more years, then regress to a resting stage for up to two months before starting to grow a new hair fiber again. At any time on a healthy human scalp, about 80% to 90% of the hair follicles are growing hair. These active follicles are in what is called the anagen phase. That leaves up to 10% to 20% percent of scalp hair follicles in a resting state called telogen, when they don't produce any hair fiber. Changes in actual amount of hair fall occur in number of hair loss conditions including anagen effluvium, acute and chronic telogen effluvium, alopecia areata, cicatricial alopecia, male pattern hair loss (MPHL) and female pattern hair loss (FPHL).
Men commonly complain of increased hair loss or hair shedding, especially after washing their hair. Changes in actual amount of hair fall occur in number of hair loss conditions including anagen effluvium, acute and chronic telogen effluvium, alopecia areata, cicatricial alopecia and male pattern hair loss (MPHL).
Female pattern hair loss (FPHL) is the most common cause of hair loss encountered in clinical practice for women (Messenger et al. 2010). FPHL is a complex polygenic disorder characterised clinically by diffuse hair thinning over the mid frontal scalp and histologically by hair follicle miniaturization. The proportion of miniaturized follicles increases with the severity of hair loss (Messenger et al. 2006). FPHL adversely impacts quality of life and the prevalence of FPHL increases with age. In a population study of over 700 women, FPHL was found in 12% of women aged 20-29 and 57% of women aged >80. Hair loss severity also increases with age.
One such condition that results in in increased hair loss or excessive hair shedding is telogen effluvium (TE). This condition effects both men and women, occurring more commonly in women. TE is a non-scarring alopecia characterised by excessive shedding of telogen club hair diffusely from the scalp. It generally begins 8-12 weeks after a triggering event such as pregnancy, major illness or complicated surgery and is resolves within 3-6 months. Once resolved, self-limiting telogen effluvium can be retrospectively diagnosed as acute telogen effluvium (Harrison S and Sinclair R, 2002). Telogen shedding that persists beyond 6 months is called chronic telogen effluvium (CTE) (Whiting, D A 1996). CTE may be primary or secondary to a range of triggers including androgenetic alopecia (AGA), nutritional deficiency, endocrinopathy, connective tissue disease or drug induced (Messenger et al., 2010).
The aetiology of primary CTE is unknown (Whiting, D A 1996). The natural history is for continued hair shedding over many years. Long-term follow up studies of women with primary CTE (Bittencourt C, 2014) and histomorphometric and immunohistochemical examination of scalp biopsies in patients with both FPHL and CTE have confirmed that primary CTE is not a prodrome to AGA (Whiting D A, 1996).
Primary CTE most commonly occurs suddenly in females between 30 and 50 years of age. Additional clinical features commonly seen in primary CTE include bitemporal recession of the anterior hairline, a reduction in the thickness of their ponytail diameter (Whiting, D A 1996) and trichodynia (Kivanç-Altunay, İ. et al. 2003). Widening of the central part line suggests AGA and is not a feature of primary CTE. Other than identification and treatment of a triggering event such as hypothyroidism, there is no known treatment for acute telogen effluvium (ATE) or CTE (Garcia-Hernandez M J et al. 1999). Treatments commonly used for AGA such as finasteride, cyproterone acetate, spironolactone and flutamide do not work in TE (Messenger A et al. 2010). Currently, the only suggested treatment for CTE is topical minoxidil, however results are variable and often disappointing. One study demonstrated an improvement in 55.2% of patients studied, using 5% topical minoxidil for men and 5% topical minoxidil with 50 mg of cyproterone acetate for women (Garcia-Hernandez et al. 1999). Only 25.2% of patients had a moderate response to treatment (Garcia-Hernandez et al. 1999). There are currently no FDA or TGA treatments available for chronic telogen effluvium.
There is a requirement for new treatments for conditions of hair loss and excessive hair shedding for both men and women, including telogen effluvium. There is also a requirement for rapid, inexpensive and simple tools for monitoring excessive hair shedding.